Detect Traps allows a Rogue to find traps laid out by others. When paired with Disarm Trap, a rogue becomes essential for the safekeeping of any band of dungeon explorers.
Many rogues have expressed great displeasure over the change of Detect Traps to a passive in patch 1.11 (Shadow of the Necropolis). They claim that they enjoyed spamming the "Swirly Ball" (a reference to the animation of the old, castable spell), and now have "nothing to do during buff downtime at raids". Despite the many complaints, Blizzard has yet to make a formal response.
Other rogues also tell of not being able to see hunter traps, nor being unable to disarm them, until it's too late and the rogue is caught in it.
Edit
